PURPOSE: In this project, we will use a combination of computational and experimental techniques to characterize c-Myc dynamics in a variety of cell systems in response to c-Myc activating cues. By allowing us to study emergent properties that are not evident at the level of smaller-scale interactions, this type of approach will provide novel strategies for manipulating circuit functions, as well as new ways to combat cancers in which c-Myc dynamics are deregulated. MATERIALS AND METHODS: To measure the dynamics of circuit components, we will primarily use long-term time-lapse fluorescence microscopy of living individual cells in which c-Myc has been fluorescently tagged. We will use chemical and genetic perturbations to alter c-Myc dynamics and determine the effects on cellular functions. Using computational modeling, we will integrate these data with measurements of cellular outcomes to predict pathway behavior in response to specific perturbations. PROGRESS IN FY2015: Using mouse embryonic fibroblasts in which the gene encoding the green fluorescent protein GFP has been inserted into the endogenous loci of both c-Myc alleles, we have identified novel, complex dynamics of c-Myc activation following stimulation. We have characterized these dynamics in terms of general network structure responsible for generating the response. Current work is focused on obtaining a more detailed mechanistic understanding of this regulation, as well as identifying phenotypic comsequences of the observed c-Myc dynamics. We have also extended this work to look at co-regulation of the c-Myc network and the p53 network in response to various stimuli. This work is being performed in collaboration with David Levens (LP/CCR).